package com.hmdp.service.impl;

import cn.hutool.core.util.StrUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.dto.Result;
import com.hmdp.entity.Shop;
import com.hmdp.mapper.ShopMapper;
import com.hmdp.service.IShopService;
import com.hmdp.utils.CacheClient;
import com.hmdp.utils.RedisConstants;
import com.hmdp.utils.SystemConstants;
import org.springframework.data.geo.Distance;
import org.springframework.data.geo.GeoResult;
import org.springframework.data.geo.GeoResults;
import org.springframework.data.redis.connection.RedisGeoCommands;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.domain.geo.GeoReference;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.Resource;
import java.util.*;
import java.util.concurrent.TimeUnit;

/**
 * <p>
 * 服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class ShopServiceImpl extends ServiceImpl<ShopMapper, Shop> implements IShopService {

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private CacheClient cacheClient;

    @Override
    public Result queryById(Long id) {
        //缓存穿透
//        Shop shop = cacheClient.queryWithPassThrough(RedisConstants.CACHE_SHOP_KEY, id, Shop.class, this::getById,
//                RedisConstants.CACHE_SHOP_TTL, TimeUnit.MINUTES);
        //互斥锁解决缓存击穿
//        Shop shop = this.queryWithMuteX(id);
        //逻辑过期解决缓存击穿
        Shop shop = cacheClient.queryWithLogicExpire(RedisConstants.CACHE_SHOP_KEY, id, Shop.class, this::getById,
                RedisConstants.CACHE_SHOP_TTL, TimeUnit.SECONDS);
        if (shop == null) {
            return Result.fail("店铺信息不存在！");
        }
        return Result.ok(shop);
    }

//    private static final ExecutorService CACHE_REBUILD_EXECUTOR = Executors.newFixedThreadPool(10);

    //缓存穿透
    /*public Shop queryWithLogicExpire(Long id) {
        String redisKey = RedisConstants.CACHE_SHOP_KEY + id;
        //1.从redis中查询商铺缓存
        String shopJson = stringRedisTemplate.opsForValue().get(redisKey);
        //2.判断是否存在
        if (StrUtil.isBlank(shopJson)) {
            //3.不存在，直接返回
            return null;
        }
        //4.存在 判断是否过期
        RedisData redisData = JSONUtil.toBean(shopJson, RedisData.class);
        Shop shop = JSONUtil.toBean((JSONObject) redisData.getData(), Shop.class);
        LocalDateTime expireTime = redisData.getExpireTime();
        //5.判断是否过期
        if (expireTime.isAfter(LocalDateTime.now())) {
            //5.1 未过期，直接返回商铺信息
            return shop;
        }
        //5.2 已过期，需要缓存重建
        //6.缓存重建
        //6.1 获取互斥锁
        String lockKey = RedisConstants.LOCK_SHOP_KEY + id;
        //6.2 判断是否获取锁成功
        boolean isLock = this.tryLock(lockKey);
        if (isLock) {
            //6.3 成功，开启独立线程，实现缓存重建
            CACHE_REBUILD_EXECUTOR.submit(() -> {
                try {
                    //重建缓存
                    this.saveShop2Redis(id, 20L);
                } catch (Exception e) {
                    throw new RuntimeException(e);
                } finally {
                    //释放锁
                    this.unLock(lockKey);
                }
            });
        }
        //6.4 返回过期的商铺信息
        return shop;
    }*/

    //互斥锁解决缓存击穿
//    public Shop queryWithMuteX(Long id) {
//        String redisKey = RedisConstants.CACHE_SHOP_KEY + id;
//        //1.从redis中查询商铺缓存
//        String shopJson = stringRedisTemplate.opsForValue().get(redisKey);
//        //2.判断是否存在
//        if (StrUtil.isNotBlank(shopJson)) {
//            //3.存在，直接返回
//            return JSONUtil.toBean(shopJson, Shop.class);
//        }
//        //判断命中的是否是空值
//        if (shopJson != null) {
//            return null;
//        }
//        //4.实现缓存重建
//        //4.1 获取互斥锁
//        String lockKey = "lock:shop:" + id;
//        Shop shop;
//        try {
//            boolean isLock = this.tryLock(lockKey);
//            //4.2 判断是否获取成功
//            if (!isLock) {
//                //4.3 失败，则休眠并重试
//                Thread.sleep(50);
//                return this.queryWithMuteX(id);
//            }
//            //4.4 成功，根据id查询数据库
//            shop = this.getById(id);
//            //模拟重建的延迟
//            Thread.sleep(200);
//            //5.不存在，返回错误
//            if (shop == null) {
//                //将空值写入redis
//                stringRedisTemplate.opsForValue().set(redisKey, "", RedisConstants.CACHE_NULL_TTL, TimeUnit.MINUTES);
//                //返回错误信息
//                return null;
//            }
//            //6.存在，写入redis
//            stringRedisTemplate.opsForValue().set(redisKey, JSONUtil.toJsonStr(shop), RedisConstants.CACHE_SHOP_TTL, TimeUnit.MINUTES);
//        } catch (InterruptedException e) {
//            throw new RuntimeException(e);
//        } finally {
//            //7.释放互斥锁
//            this.unLock(lockKey);
//        }
//        //8.返回
//        return shop;
//    }

    //缓存穿透
//    public Shop queryWithPassThrough(Long id) {
//        String redisKey = RedisConstants.CACHE_SHOP_KEY + id;
//        //1.从redis中查询商铺缓存
//        String shopJson = stringRedisTemplate.opsForValue().get(redisKey);
//        //2.判断是否存在
//        if (StrUtil.isNotBlank(shopJson)) {
//            //3.存在，直接返回
//            return JSONUtil.toBean(shopJson, Shop.class);
//        }
//        //判断命中的是否是空值
//        if (shopJson != null) {
//            return null;
//        }
//        //4.不存在，根据id查询数据库
//        Shop shop = this.getById(id);
//        //5.不存在，返回错误
//        if (shop == null) {
//            //将空值写入redis
//            stringRedisTemplate.opsForValue().set(redisKey, "", RedisConstants.CACHE_NULL_TTL, TimeUnit.MINUTES);
//            //返回错误信息
//            return null;
//        }
//        //6.存在，写入redis
//        stringRedisTemplate.opsForValue().set(redisKey, JSONUtil.toJsonStr(shop), RedisConstants.CACHE_SHOP_TTL, TimeUnit.MINUTES);
//        //7.返回
//        return shop;
//    }

    @Transactional
    @Override
    public Result update(Shop shop) {
        Long id = shop.getId();
        if (id == null) {
            return Result.fail("店铺id不能为空");
        }
        //1.更新数据库
        this.updateById(shop);
        //2.删除缓存
        stringRedisTemplate.delete(RedisConstants.CACHE_SHOP_KEY + id);
        //返回
        return Result.ok();
    }

    //获取锁
    /*private boolean tryLock(String key) {
        Boolean flag = stringRedisTemplate.opsForValue().setIfAbsent(key, "1", 10L, TimeUnit.SECONDS);
        return BooleanUtil.isTrue(flag);
    }

    //释放锁
    private void unLock(String key) {
        stringRedisTemplate.delete(key);
    }

    //缓存重建（缓存预热 ）
    public void saveShop2Redis(Long id, Long expirySeconds) {
        //1.查询店铺数据
        Shop shop = this.getById(id);
        try {
            Thread.sleep(200L);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        //2.封装逻辑过期时间
        RedisData redisData = new RedisData();
        redisData.setData(shop);
        redisData.setExpireTime(LocalDateTime.now().plusSeconds(expirySeconds));
        //3，写入Redis
        stringRedisTemplate.opsForValue().set(RedisConstants.CACHE_SHOP_KEY + id, JSONUtil.toJsonStr(redisData));
    }*/

    @Override
    public Result queryShopByType(Integer typeId, Integer current, Double x, Double y) {
        //1.判断是否需要根据坐标查询
        if (x == null || y == null) {
            //不需要坐标查询
            // 根据类型分页查询
            Page<Shop> page = query()
                    .eq("type_id", typeId)
                    .page(new Page<>(current, SystemConstants.DEFAULT_PAGE_SIZE));
            // 返回数据
            return Result.ok(page.getRecords());
        }
        //2.计算分页参数
        int from = (current - 1) * SystemConstants.DEFAULT_PAGE_SIZE;
        int end = current * SystemConstants.DEFAULT_PAGE_SIZE;
        //3.查询redis，按照距离排序、分页。结果：shopId、distance
        //GEOSEARCH BYLONLAT x y BYRADIUS 10 WITHDISTANCE
        String key = RedisConstants.SHOP_GEO_KEY + typeId;
        GeoResults<RedisGeoCommands.GeoLocation<String>> results = stringRedisTemplate.opsForGeo().search(
                key,
                GeoReference.fromCoordinate(x, y),
                new Distance(5000),
                RedisGeoCommands.GeoSearchCommandArgs.newGeoSearchArgs().includeDistance().limit(end)
        );
        //4.解析出id
        if (results == null) {
            return Result.ok();
        }
        List<GeoResult<RedisGeoCommands.GeoLocation<String>>> list = results.getContent();
        if (list.size() <= from) {
            //没有下一页了 结束
            return Result.ok(Collections.emptyList());
        }
        //4.1 截取from ~ end的部分
        List<Long> idList = new ArrayList<>();
        Map<String, Distance> distanceMap = new HashMap<>(list.size());
        list.stream().skip(from).forEach(result -> {
            //4.2 获取店铺id
            String shopIdStr = result.getContent().getName();
            idList.add(Long.valueOf(shopIdStr));
            //4.3 获取距离
            Distance distance = result.getDistance();
            distanceMap.put(shopIdStr, distance);
        });
        //5.根据id查询Shop
        String idStr = StrUtil.join(",", idList);
        List<Shop> shopList = lambdaQuery()
                .in(Shop::getId, idList)
                .last(" ORDER BY FIELD(id, " + idStr + ")")
                .list();
        //遍历设置店铺的距离
        for (Shop shop : shopList) {
            shop.setDistance(distanceMap.get(shop.getId().toString()).getValue());
        }
        //6.返回
        return Result.ok(shopList);
    }
}
